Dr. Ralph Gomory is one of the key consultants behind the US Department of Homeland Security's GetReady.gov website.
In this interview he explains how he became concerned that the public should have concrete things it can do to prepare for and respond to the possibility, even the eventuality (as he sees it) of attack.
This is a very disturbing conversation, especially as it is conducted in almost a matter-of-fact, light-hearted manner-- as if the topic of conversation was the weather.
Gomory seems to consider future attacks as inevitable, more numerous, and coming from more sources-- because he believes that the technological know-how to make terror weapons is becoming more widespread.
The impression I got from him is that he considers the growing danger of terrorism as becoming a normal cost of our technologically literate society. He also seems overly confident in society's ability to defend itself-- without speaking of any prospect that people could learn to solve their problems without ever resorting to violence.
To get an idea of how the latter might be possible, I recommend listening to Jonas Salk's cautious optimism at: http://www.archive.org/details/openmind_ep1234